Circuit breaker



Sept. 5, 1944. H. P. PlNKHAM ErAL CIRCUIT BREAKER 4 Sheets-Sheet 3 Filed July 22, 1942 a MW Sept. 5 1944. H. P. PINKHAM ET AL. 2,357,603

CIRCUIT BREAKER Y Filed July 22, 1942 4 Sheets-Sheet 4 Patented Sept. 5, 1944 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Henry P. Pinkham and Chester D. Ainsworth,

Wollaston, Mass., assignors to Allis-Chalmers Manufacturing Company,

Milwaukee, Win, a

16 Claims.

. This invention relates in general to oil circuit breakers and relates particularly to an improved means for supporting, controlling and operating a large multi-pole heavy duty circuit breaker.

In the prior art circuit breakers of this type, the individual pole unit was the functional and structural basic unit. Such pole unit was designed individually for its circuit making and breaking function and, if a three-pole unit was desired, three of such units were placed on a suitable support, were coupled together, and thus caused to function as a three-pole breaker. This conception of design resulted in a composite structure made up of several more or less disjointed parts; that is, the foundation or supporting unit, three more or less independent pole unit tops, an end box at one end of the structure for housing the linkage connecting the operating mechanism to the operator, an additional housing at the opposite end of the circuit breaker for housing an accelerating means, and separate housings between the individual pole units for the operating means and for the control wiring.

It is therefore a general object of the present invention to provide a multi-pole circuit breaker of the above type with improvements which will result in the lowest possible manufacturing cost and at the same time eifect an integrated, unitary, simplified structure that will require the least space and that will provide for all functional relationships of the circuit breaker during the .severest interrupting duty cycle within its rating.

In prior structures of the above composite type,

the foundation or support has included a metal base plate, of perhaps one inch thickness, on which three independent drawn steel domes are welded. As the weights of three-pole heavy duty oil circuit breakers, in the ordinarily encountered voltage ranges, are from ten to twenty-five thousand pounds, of which the oil itself may weigh from two to eight thousand pounds, such a base plate has been reinforced by a conventional beam truss structure. Such beam truss structure involves braces and cross braces to prevent the base plate from sagging or breaking, and such braces greatly limit the accessibility for inspection and repair of the under oil circuit breaker parts when the tanks have been removed,

It is therefore a specific object of the present invention to provide in a multi-pole heavy duty circuit breaker, a foundation or supporting structure which of itself has a depth of section sumcient to supply the necessar strength and rigidity without reinforcement.

In the prior art circuit breaker above refer ed to, the bushing current transformer leads and other wiring for control and operation of the sir cuit breaker extended through conventie metal conduits on the outer side of. the brea e.- from the current transformers on the bushing; to the control box usually located at the front of the circuit breaker. This provided a costly st ture from both manufacturing and maintenance standpoints.

It is a further object of the present invention to provide, in a self-supporting structure of the above type, for the enclosure of the control wire ing and current transformer leads in a duct formed by the elements of the self-supporting structure.

It is also an object of the present invention to provide, in a multi-pole circuit breaker provided with current transformers, for prevention of oil syphon action along the insulation of the transformer leads.

It-is a further object of this invention to provide for an improved guiding and supporting or the removable tank portions of a circuit breaker.

It is a further object of this invention to pre vent the passage of hot gases from the pressure space of a circuit breaker to the end box or control cabinet by providing an improved rotatable. rather than slidable. connection of the breaker pull rod where this rod enters the pressure space.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 is a side elevational view of a circuit breaker embodying the present invention;

Fig. 2 is a left end view of the circuit breaker shown in Fig. 1;

40 Fig. 3 is a right end view shown in Fig. 1;

Fig. 4 is a sectional view IV-IV of Fig. 5;

Fig. 5 is a sectional view taken along the line 45 VV of Fig. 3;

Fig. 6 is a partial sectional the line VI-VI of Fig. 1;

Fig. 7 is a plan view of the circuit breaker shown in Fig. 1;

Fig. 8 is a vertical sectional view taken along the line VIIIVHI of Fig. 7;

Fig. 9 is a transverse sectional the line IX-IX of Fig. 7;

Fig. 10 is a right end view of the circuit breaker 65 shown in Fig. 8;

of the circuit breaker taken along the line view taken along view taken along Fig. 11 is a sectional view taken along the lines XI-JCI of Fig, 7;.

Fig. 12 is a vertical sectional view, similar to the view shown in Fig. 8, but including the circuit breaker operating mechanism, portions of the tanks and additional parts of the supporting structure;

Fig. 13 is a vertical sectional view taken along the line XIII-XIII of Fig. 12;

Fig. 14 is a sectional view taken along the line XIV-XIV of Fig. 15 illustrating on an enlarged scale the means for sealing the opening for the circuit breaker operating member;

Fig. 15 is a plan view of the operating bell crank sealing chamber;

Fig. 16 is a sectional view taken along the line XVI-XVI of Fig. 14;

Fig. 17 is an end view of the bell crank operating lever;

Fig. 18 is a side view of the bell crank lever shown in Fig. 17; and

Fig, 19 is an enlarged vertical sectional view taken along the line XIX-XX of Fig. 12 and illustrating the circuit breaker in its completely assembled form.

The invention has been illustrated in the drawings as applied to a three-pole circuit breaker. The general assembly of this circuit breaker is shown more clearly in Figs. 1, 2 and 3 and consists essentially of a top or supporting section, shown in Figs. 7, 8, 9 and 10, supported on legs or corner posts with a housing 92 forthe circuit breaker operator attached to one end thereof. The six bushings 26 carry the circuit conductors through the top 2| to the separable contact members enclosed in oil in the three tanks 23.

The top or supporting section, shown more clearly in Figs. 7, 8, 9 and 10, consists essentially of an inner section and an outer section. The outer section is formed of a shell or crown sheet 2!, the pole mechanism support brackets 70 and 14, the bell crank support housing M, the end plates 69 and the crossover duct 95. The inner section consists essentially of a base plate 23, two longitudinal angle members 22 welded along the side edges of the base plate 23 and the interpole barriers 68. The final assembly of the two sections of the top structure is accomplished by dropping the inner section into the inverted outer section and welding the edges of the angle 22 along the top and sides of the shell 2 I This top structure forms the foundation or supporting structure for the circuit breaker mechanism including the tanks 24 which are filled with oil. Such a foundation structure needs no external support for it has suflicient depth of section to provide the necessary rigidity. It is easy access to the under oil circuit breaker parts for inspection, maintenance and repair.

This self-supporting foundation structure provides advantages other than the accessibility involved in the elimination oi? the conventional beam truss support. The manufacturing process is simplified thereby providing a considerable saving in manufacturing cost in addition to the saving in material involved in the elimination of the beam truss support.

A further saving in material is made and other advantages obtained by fabricating the angles 22 and crown sheet 2i as shown, to form a duct 33 running the full length of both sides of the circuit breaker. This duct 33 and the crossover duct 95, without the necessity of additional conduit and expensive conduit fittings utilized in prior art plate and dome type circuit breakers, provides a means for bringing the leads 86, connected to the bushing current transformers 21, to the control cabinet 92 in just as completely isolated relation as if the conventional conduit system outside of the domes was utilized. However, the ducts 33 and 95 are more completely and more permanently water-tight and much more convenient and accessible than the conventional conduit system.

The base plate 23 has three large holes 33 therein through which the two bushings 23 of 'each pole extend. These bushings 26 support the fixed contact structure and the arc extinguishing chamber 29. The moving contacts 28 are supported on an electrically conductive bridging member 35 which is carried by an operating rod 30. In the circuit breaker illustrated in the present embodiment, the separable contacts make and break the circuit in oil supplied in the removable tank 25.

The crown sheet 2i is a single sheet of metal 40 bent into substantially the shape of a short, wide,

self-supporting due to the inherent strength derived from the internal box girder formed in the illustrated embodiment by the longitudinal angle irons 22 welded continuously along the edges thereof to both the top and skirtof the crown sheet 2 I. This box girder could also be formed by utilizing longer depending slides of the crown sheet 2|, bent inward and upward and welded along the top inthe same manner as the upper edge of angle 22.

Additional rigidity is supplied by end plates 69 and the interpole barrier 68 welded to the crown sheet 2|, the angles 22 and the base plate 23. As this structure is self-supporting, it permits of elimination of the beam truss supporting structure, necessary in the conventional plate and dome construction, and, therefore, permit inverted U. As the only openings therein are those through which the bushings 26 extend, this shell 2i forms a smooth top for the circuit breaker which avoids crevices which can collect dirt and moisture and invite corrosion and provides maximum protection against wind driven sand, snow, sleet and water. The top is unbroken for extension therethrough of oil filling pipe con-' nections, gas separators, or emergency vents as in the usual construction.

The present invention provides for the above elements in the space aiiorded in the corners 01' each pole unit. The filling connections are as shown at in Figs. '7, 9 and 10 and extend one in each pole unit up through the base plate 23, where they may be easily and simply connected to an existing pipe system without extending through the top 2!. The gas separators and emergency vents 48 are similarly supported by the base plate 23, and extend therethrough one in each pole unit.

The gas separator 48 is shown in detail in Fig. 11 as being a pipe threaded into a retaining ring 16 welded to the base plate 23. The gas is permitted to escape from the pressure compartment through the pipe 48 around a diaphragm 11 normally held in place by means of a spring 18. Under pressure, the gas is permitted to escape without the oil escaping also. If extreme pressure develops, the diaphragm H is blown out to form an emergency vent. The separator 48 may also be connected by a pipe connection at its lower end to an existing pipe system.

The tanks 23 are raised and lowered from the position shown in Figs. 1 and 2 by means of a cable 65 having one end fastened to the frame structure as shown at 94 in Fig.1. Each tank 24 has sheaves 6| which cooperate with sheaves 62 on a bracket 63. to raise or lower any individual tank. The bracket 63 may be placed on any of the lifting lugs 64 so that any circuit breaker tank can be raised or lowered. The cable 65 is led over a sheave B to winding or unwinding sheaves on the shaft 66 operated by a crank 81 as shown more clearly in Figs. 1 and 2.

A novel and improved arrangement for supporting the tanks 24 and for guiding them into their raised position is shown in detail in Fig. 6. Bolt 50 are rigidly held in the foundation or supporting structure by means of the upper shoulder on the collar 51 on the bolt 50 and a supporting block 55 welded to the angle member 22 and to the base plate 23. This construction permits the tank 24 and the oil therein to be supported directly by the angles 22 which are the strength providing elements of the supporting structure. The lower shoulder of the collar 51. provides a stop against which the lug 55 may be raised. The length of collar 51 is so dimensioned that it provides for the correct compression of the tank gasket. This metal to metal stop prevents compression of the gasket beyond the elastic limit thereof.

The guiding lug 56 is welded to the tank 24 and is provided with a hole therein of a diameter slightly larger than the bolt 50. By providing the rigidly held bolt 50 and the guiding lug 56, the tank is easily guided when raised to its position where it is alined with the tank gasket held in the retaining ring 49. The use of the rigidly held tank bolts as a guiding means for the tank, avoids the necessity of a machined flange for a guide. With the present construction the tank gasket and gasket retaining ring can be supported as well on the removable tank.

The operator (not shown) for the circuit breaker is housed in the housing 92 shown in Figs. 1 and 3. Movement of this operator must be transmitted to the movable contacts 28 for operation of the circuit breaker. This necessitates bathing or sealing of the operating linkage where it enters the pressure chamber in order to keep the hot pressure gases, generated by the products of arc interruption, out of the control cabinet and the secondary wiring therein. In prior-circuit breakers of this type, the operating rod has entered the pressure chamber as a sliding member and such sliding member has been difilcult to baflle and seal.

In the present invention, the operating link 45 transmitting motion from the operator to the pull rod 33 is connected to a shaft 40 which, combined with a special housing 4|, provides an effective seal against the hot pressure gases. The general arrangement is shown more clearly in Fig. 12 and detail views of shaft 40 and the housing 4| are shown in Figs. 14, 15, 16, 17 and 18. The shaft 40 has a single crank arm 43 connected to the operating link 45. The shaft 40 has two arms 42 connected to the pull rod 33.

The bearing surfaces for the shaft 40 are between the crank arm 43 and the crank arms 42. The housing 4| for this shaft 40 is narrowed at the point of the bearing surfaces of the crank, so that when the cover 44 is in position as shown in Fig. the arm 43 extends on the control cabinet side of the housing 4 I. The arms 42 extend from the shaft 40 on the pressure compartment side of the housing 4| which is exposed to the hot gases. Due to the shoulders turned on the crank arms 42 and 43, and further due to the fact that the bearing clearances are of the order of .001 to .002 of an inch, the path through which hot gases must flow to get from the pressure compartment to the control cabinet-is tortuous and very small, and therefore effectively seals against passage of such gases.

The pull rod 39, transmitting motion from the shaft 40 to the contact operating members, is made in sections and baflled where the rod 39 passes through the plate 68, by means of a gasket 3| held in place by retaining member 32. The pull rod 39 connects through links 38 to the operating rod 30 for transmitting opening and closing movement to the movable contacts 28. Shock absorbers 86 and 81 are supplied, for stopping the closing and opening movements of the operating mechanism. A Z-shaped bar 88, placed between the two links 38 connected to the operating rod 30, cooperates with the shock absorbers 86 and 81. Motion of the operating rods 30 is guided by the rollers 36 mounted in a supporting member 31 carried by the brackets IT.

The bushing current transformers 21 have leads extending to terminals 82 on a terminal plate 83 in the housing 8|. This housing 8| is welded into openings in the angle member 22 in pressure tight relation. The terminal plate 83 is also mounted on the housing 8| in a manner so that the hot gases cannot escape into the wiring duct 33. The transformer leads 84 extend from the terminal plate 83 to the control box 92 through the duct 33 formed by the plate 2| and the angle 22 and through the crossover duct 95.

The leads from the bushing current transformer 27 must extend from the pressure compartment out through some type of pressure baffling device Where these leads leave the pressure compartment. In the prior art circuit breakers utilizing a pipe conduit system for the transformer leads. the transformer leads were taken from the pressure compartment through a pressure baffle and thence through the conduit to the control cabinet. In such cases, leakage of oil into the conduit has been found, clue to the fact that the pressure will start a syphon action in the insulation around the transformer leads, which will continue to syphon oil from the pressure chamber drop by drop. By providing terminal plates at each pole, a break in the terminal wire insulation is obtained, and syphoning action in the small capillary spaces of the terminal wires is prevented.

Helical coil compression springs 46 are provided to impart a high rate of acceleration to the movable contact members 28 during opening of the circuit breaker. A hand hole covered by a plate 41 is provided for adjustment of this spring. Adjustment of this spring is necessary and access to the adjustment is desirable when the breaker is in place and the tanks are up in the position shown in Fig. 19.

In the illustrative embodiment of the invention here shown and described, the fabrication of parts has generally been referred to as welding, however, this term was used in an illustrative rather than limiting sense, as other methods of fabrication may also be utilized. Where elements are referred to as Welded and are shown as unitary, such parts may be either integral or joined. Many of the aspects of this invention are not limited to a multi-pole circuit breaker, but may as well be utilized in a single pole circuit breaker.

Although but one embodiment of the present invention has been illustrated and described it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the-spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A supporting structure for the plurality of pole units of a plural pole unit circuit breaker comprising a member covering said pole units. and a strengthening member unitary with said covering member to form therewith a longitudinal enclosed duct extending to each of said pole units.

2. In a circuit breaker, a supporting structure comprising a covering member provided with a top and depending sides, and means comprising a strengthening member spaced from one of said depending sides rigidly joined to said covering member along said top for forming with said top and said side a box girder providing longitudinal rigidity to said supporting structure.

3. In a plural pole unit circuit breaker, a structure for supporting said plurality of pole units comprising a covering member for said plurality of pole units provided with a top and depending sides, and means comprising a strengthening member unitary with said covering member along substantially the entire length of said top and one of said sides for forming therewith a strengthening section providing longitudinal rigidity to said supporting structure and for forming therewith an enclosed duct extending to each of said pole units.

4. A self-supporting structure for the plurality of pole units of a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member rigidly joined to said covering member along said top for forming with said top and said sides a box girder providing longitudinal rigidity, a barrier plate positioned between adjacent pole units and rigidly joined to said covering member top and to said box girder, and an end plate positioned at each end of said structure and rigidly joined to said top and said sides of said covering member.

5. A supporting structure for the plurality of pole units of a plural pole unit circuit breaker comprising a member covering said pole units, a strengthening member unitary with said covering member to form therewith a longitudinal enclosed duct extending to each of said pole units, bushings extending through said covering member, a transformer mounted on one of said bushings, and electrical conductors connected to said transformers and extending in said duct.

6. A supporting structure for the plurality of pole units of a plural pole unit circuit breaker comprising a member covering said pole units, a strengthening member unitary with said covering member to form therewith a longitudinal enclosed duct extending to each of said pole units, bushings extending through said covering member, a transformer mounted on one of said bushings, a terminal housing supported by said strengthening member, terminals carried by said housing and positioned so that one end thereof extends into said duct, and the other end thereof extends into said housing, insulated electrical connections from said transformers to said other end of said terminals, and insulated electrical connections from said one end of said terminals extending in said duct.

'7. A self-supporting structure for the plurality of pole units of a plural pole circuit breaker comprising a covering member for said pol units provided with a top and depending sides, an angl member having one edge thereof rigidly Joined to said covering member along said top and having the other edge thereof rigidly joined to one of said sides to form with said top and said side a box girder providing longitudinal rigidity, a separate tank for housing the separable contact members of each of aid pole units, and means for supporting said tanks from said box girder.

8. -A self-supporting structure for the plurality of pole .units of a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member having one edge thereof rigidly joined to said covering member along said top and having the other edge thereof rigidly joined to one of said sides to form therewith a box girder providing longitudinal rigidity, a separate tank for housing the separable contact members of each of said pole units, and means for removably supporting said tanks and for guiding said tanks when raised to contact enclosing position, said means comprising a fastening'member rigidly upported by said box girder.

9. A self-supporting structure for the plurality of pole units of a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member having one edge thereof rigidly joined to said covering member along said top and having the other edge thereof rigidly joined to one of said sides to form therewith a box girder providing longitudinal rigidity, a separate tank for housing the separable contact members of each of said pole units, means for removably supporting said tanks and for guiding said tanks when raised to contact enclosing position, said means comprising a fastening member rigidly supported by said box girder, a gasket between said supporting structure and said tank, and means for limiting the compression of said gasket when said tank is fastened in said raised position.

10. In a circuit breaker provided with a housing enclosing the separable contact members and having a fixed and a removable portion, a gasket between said fixed and said removable portion, a first fastening and guiding member rigidly supported by said fixed portion, a cooperating fastening and guiding member rigidly supported by said removable portion, and means comprising said fastening members for compressing said gasket only within the elastic limit thereof when said removable portion is fastened to said fixed portion.

11. In a circuit breaker, the combination of a movable contact, an interrupting chamber enclosing said contact under pressure during circuit interruption and an operator external to said chamber, with a shaft journaled in bearing surfaces positioned in a wall of said pressure chamber and provided with a crank arm extending into said pressure chamber and connected to said contact and further provided with a second crank arm extending externally of said chamber and connected to said operator, and means comprising said bearing surfaces and portlons of said cranks providing a tortuous path of small cross-section from said interrupting chamber to a point external thereof.

12. A self-supporting structure for the plurality of pole units of a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member rigidly joined to said covering member along said top and one of said sides to form therewith a box girder providing longitudinal rigidity, a barrier plate positioned between adjacent pole units and rigidly Joined to said covering member top and to said box girder to form separate pole unit compartments under pressure during circuit interruption, a bottom plate rigidly joined to said box girder and forming a portion of the wall of said compartments, an emergency vent for escape of said gases positioned in said bottom plate.

13. A self-supporting structure for the plurality of pole units of a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member rigidly Joined to said covering member along said top and one of said sides to form therewith a box girder providing longitudinal rigidity, a barrier plate positioned between adjacent pole units and rigidly Joined to said covering member top and to said box girder to form separate pole unit compartment under pressure during circuit interruption, a bottom plate rigidly Joined to said box girder and forming a portion of the wall of said compartments, a pipe connection through said bottom plate for supplying oil to said compartments.

14. A self-supporting structure for the plurality oi pole units oi. a plural pole circuit breaker comprising a covering member for said pole units provided with a top and depending sides, an angle member rigidly joined to said covering member along said top for forming with said top and said sides a box girder providing longitudinal rigidity, a barrier plate positioned between adjacent pol units and rigidly Joined to said covering member top and to said box girder,

an end plate positioned at each end of said structure and rigidly joined to said top and said sides of said covering member, and an angle member unitary with said top and one of said end plates forming an enclosed duct opening into said box girder.

15. In a plural pole unit circuit breaker, a structure for supporting said plurality of pole units comprising a covering member for said plurality of pole units provided with a top and depending sides, means comprising a strengthening member unitary with said covering member along substantially the entire length of said top and one of said sides for forming therewith a strengthening section providing longitudinal rigidity to said supporting structure and for forming therewith an enclosed duct extending to each of said pole units, an end plate positioned at one end of said structure and rigidly joined to said top and said sides or said covering member, and an angle member unitary with said top and said end plate forming an enclosed cross duct joining said first mentioned duct.

16. In a plural pole unit circuit breaker, a structure for supporting said plurality of pole units comprising a covering member for said plurality of pole units provided with a top and depending sides, and means comprising a plurality of angle members one of which is rigidly joined to said covering member along substantially the entire length of said top and one of 'said sides and another of which is similarly joined on said top and the other of said sides for forming therewith a strengthening section providing longitudinal rigidity to said supporting structure and for forming therewith enclosed ducts extending on each side of said structure to each of said pole units.

HENRY P. PINKHAM.

CEES'IER D. AJNSWORTH. 

